WBR0529

Author	[[PageAuthor::Rim Halaby, M.D. [1]]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Pharmacology
Sub Category	SubCategory::General Principles
Prompt	[[Prompt::A 72 year old male patient presents to the emergency department for high grade fever and altered mental status. Blood cultures grow ESBL-producing E. coli. Based on image shown below, at which specific site on penicillin G does the organism's beta-lactamase act? ]]
Answer A	AnswerA::A
Answer A Explanation	AnswerAExp::This is not the site of beta-lactamase action.
Answer B	AnswerB::B
Answer B Explanation	AnswerBExp::This is not the site of beta-lactamase action.
Answer C	AnswerC::C
Answer C Explanation	AnswerCExp::This site on the beta-lactam ring is the site that beta-lactamases use to break down penicillin and thus acquire resistance.
Answer D	AnswerD::D
Answer D Explanation	AnswerDExp::This is not the site of beta-lactamase action.
Answer E	AnswerE::E
Answer E Explanation	AnswerEExp::This is not the site of beta-lactamase action.
Right Answer	RightAnswer::C
Explanation	[[Explanation::Extended spectrum beta-lactamase (ESBL) producing bacteria, such as E.coli or Klebsiella species, acquire resistance to penicillin and its derivatives by the action of beta-lactamase enzyme which hydrolyzes the beta-lactam ring of the antibiotic and prevents its action. The penicillin G structure is shown in the image above. Beta-lactam is the ring structure that is hydrolyzed by beta-lactamase enzyme Educational Objective: Beta-lactam ring on penicillin G is an important site for resistance by ESBL-producing bacteria. Educational Objective: References: ]]
Approved	Approved::No
Keyword	WBRKeyword::ESBL, WBRKeyword::producing, WBRKeyword::bacteria, WBRKeyword::E. coli, WBRKeyword::Klebsiella, WBRKeyword::urosepsis, WBRKeyword::extended, WBRKeyword::spectrum, WBRKeyword::beta-lactamase, WBRKeyword::penicillin
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::